That's what Xbox has already been doing. New "Xbox" games run best on PS5 Pro (for consoles at least). I don't think there's a single Xbox Series exclusive, everything is on PC or some other console now.
I dunno, the way Windows 11 is going these days that caveat is getting a lot of scrutiny. I would say that, in many cases, they run best on PS5 Pro full stop - at least until the GabeCube releases, for those who can afford it.